JP2017531320A - Bending of image sensors using tension. - Google Patents

Abstract

A technique for processing an image sensor chip having a curved surface includes placing a bending substrate over the first surface of the imaging sensor chip. The first surface of the imaging sensor chip includes an optical sensor that generates an electrical signal in response to received light. Processing also includes bending the bending substrate to apply a force to the image sensor chip to provide a curved imaging sensor chip. The second surface of the curved imaging sensor chip may be attached to the back substrate. The second surface is opposite the first surface. The bent substrate may be removed from the first surface of the imaging sensor chip.

Description

  Optical systems are commonly used in many devices, such as cameras, telescopes, binoculars, office equipment, and scientific equipment, to name just a few. The optical system may include lenses, mirrors, and / or one or more light sensing devices. The performance of the optical system depends, in part, on the overall design of the optical system as well as the design of each of the elements of the optical system, which shows the optical interaction between the elements. For example, the light output of one lens may be the light input of a subsequent lens or light sensing device.

  Light sensing devices, such as charge coupled devices (CCDs) or photodiodes, exist in various optical systems. Often, CCDs are organized in an array that is assembled on a silicon substrate. The portion of the optical system that provides light to the CCD array is at least in part specific details of the CCD array, such as the size of the CCD array, the resolution of the CCD array, and the positioning of the CCD array relative to the remainder of the optical system. May be designed based on

  This disclosure describes techniques and architectures for bending and shaping image sensors. Specifically, for example, a fabricated image sensor fabricated on a relatively fragile substrate, such as silicon or germanium, has a light-sensitive surface of the image sensor that is spherical, aspheric, or other It may be bent to be curved to have a shape.

  In order to bend the image sensor, the bending substrate may be bonded or deposited on the photosensitive surface of the image sensor. A force or torque is applied to the bending substrate to introduce tension to the image sensor. Tension results in bending of the image sensor to any of a number of curved shapes. The force or torque may be applied relatively uniformly or non-uniformly depending on the desired curved shape.

  This summary is provided to introduce a selection of concepts in a simplified form that are described in further detail below in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. For example, the term “techniques” may be used in the above context as well as to perform techniques as permitted throughout this document, fabricating equipment, control systems (s). , Methods (s), computer-readable instructions, modules (module (s)), algorithms, or hardware logic (eg field programmable gate arrays (EPGAs), application specific Integrated circuits (ASICs), application specific standards (ASSPs), system-on-chip systems (SOCs), coupled programmable logic circuits (CPLDs)).

  The detailed description is described with reference to the accompanying figures. In the drawings, the leftmost digit of a reference number identifies the drawing in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items or configurations.

FIG. 3 is a top view of an image sensor chip, according to various exemplary embodiments.

FIG. 6 is a side view of an image sensor chip and a bending substrate, according to various exemplary embodiments.

FIG. 3 is a side view of a bent substrate and a curved image sensor chip exposed to applied forces and torques in accordance with various exemplary embodiments.

FIG. 4 is a side view of a bending substrate and a curved image sensor chip disposed on a back substrate, according to various exemplary embodiments.

FIG. 4 is a side view of a curved image sensor chip, a bending substrate, and a back substrate, according to various exemplary embodiments.

FIG. 4 is a side view of a curved image sensor chip and back substrate after removal of the bent substrate, in accordance with various exemplary embodiments.

FIG. 3 is a side view of an image sensor chip and a bending substrate placed on top of the image sensor chip by deposition, according to various exemplary embodiments.

FIG. 3 is a side view of a curved image sensor chip and bending substrate exposed to applied forces and torques, according to various exemplary embodiments.

FIG. 6 is a side view of a curved image sensor chip and back substrate, according to various exemplary embodiments.

FIG. 3 is a cross-sectional view of an optical system including a curved image sensor chip, a bending substrate, and a back substrate, according to various exemplary embodiments.

FIG. 3 is a cross-sectional view of an optical system including a curved image sensor chip and a back substrate, according to various exemplary embodiments.

FIG. 3 is a side view of a bending substrate and image sensor chip including various notches and grooves, according to various exemplary embodiments.

1 is a top view of a bending substrate that includes a series of notches and / or grooves that are concentrically distributed around a central region of the bending substrate, in accordance with a number of exemplary embodiments. FIG.

FIG. 6 is a side view of a bent substrate and curved image sensor chip including various notches and grooves, according to various exemplary embodiments.

FIG. 6 is a side view illustrating a neutral axis, an image sensor chip, and a bending substrate, according to various exemplary embodiments.

6 is a cross-sectional view illustrating the curvature of a back substrate and a curved image sensor chip, in accordance with various exemplary embodiments. FIG.

2 is a cross-sectional view of a photosensitive surface of a curved image sensor chip, in accordance with various exemplary embodiments. FIG. 2 is a cross-sectional view of a photosensitive surface of a curved image sensor chip, in accordance with various exemplary embodiments. FIG.

FIG. 6 is a top view of an image sensor chip and a bending substrate, according to various embodiments.

FIG. 3 is a flow diagram illustrating an exemplary process for bending an image sensor chip, in accordance with some embodiments.

(Overview)
In general, an optical system includes one or more light sensing devices such as lenses, mirrors, and / or charge coupled devices (CCDs) or other devices that can convert light energy into an electrical signal. sensing) device. A plurality of CCDs may be configured in a fabricated array (eg, a pixelated array) that may be, for example, silicon, germanium, or other semiconductor material. A photosensitive device, such as an array of CCDs or other light sensing entities in any of a number of configurations fabricated on a substrate, is referred to herein as an “image sensor chip”. However, this name may not necessarily be configured to detect an image, but rather may refer to an optical sensor that may be configured to detect any (visible or invisible) optical signal. It must be noted.

  The image sensor chip may be bent so that the light-sensitive surface of the image sensor chip has a curved shape, which provides a number of advantages to the design of the optical system compared to a flat surface image sensor chip. There is. Specifically, an optical system that includes a lens and / or mirror has fewer design constraints when the optical system includes a curved image sensor chip than a flat surface image sensor chip. For example, an image sensor chip having a spherical or aspheric surface may provide a high performance optical system that provides a relatively uniform light intensity and spatial frequency response across the surface of the image sensor chip.

  In various embodiments, the image sensor chip may be bent in a process that includes bonding or depositing a “bending substrate” onto the photosensitive surface of the image sensor chip. A force or torque is applied to the bending substrate to apply a shear force to the image sensor chip. This introduces a relatively uniform tension across the surface of the chip. Such uniformity helps to avoid undesirable cracking or buckling of the relatively fragile image sensor chip. The tension causes the image sensor chip to bend into a curved shape. In some embodiments, non-uniform tension can be selectively introduced without undesirable cracking or buckling.

  In addition, the bending substrate may deform or bend the image sensor chip by tension. An image sensor chip may have a relatively low dark current when in tension compared to when it is in a compressed state. It can be beneficial to bend. Thus, the bending substrate may be designed such that a substantial portion of the area of the image sensor chip is in tension while being bent or deformed into a desired shape. Such a design may be based at least in part on the stiffness and / or thickness of the bending substrate to position the image sensor chip on the tension side of the neutral bending axis.

  In various embodiments, the curved image sensor chip is coupled to a backside substrate, which helps maintain the curved shape of the image sensor chip. Following bonding of the image sensor chip to the back substrate, the bent substrate may be removed (eg, to expose the photosensitive surface of the image sensor chip).

  In various embodiments, the combination of curved image sensor chips coupled to the bending substrate may include a stand-alone optical device, which may subsequently be incorporated into the optical system. In some implementations, such a combination may include a back substrate that is attached to the back side of the image sensor chip (eg, the side opposite the photosensitive surface). For example, a manufacturer may process an optical device that includes a combination of curved image sensor chips that are coupled to a bending substrate (and in some cases to a back substrate). Manufacturers may supply such optical devices to other manufacturers that produce optical systems. The optical device may be incorporated into such an optical system. In some implementations, the manufacturer that produces the optical system may remove the bent substrate from the image sensor chip that may serve to protect the light emitting surface from damage during storage or transport.

  In various embodiments, the curved image sensor chip combination coupled to the back substrate may include a stand-alone optical device, which may subsequently be incorporated into the optical system. For example, a manufacturer may process an optical device that includes a combination of curved image sensor chips coupled to a back substrate. Manufacturers may supply such optical devices to other manufacturers that produce optical systems. The optical device may be incorporated into such an optical system.

  With further reference to FIGS. 1-20, various exemplary embodiments will be described.

(Example environment)
FIG. 1 is a top view of an image sensor chip 100 in accordance with various embodiments. The image sensor chip 100 includes a semiconductor substrate 102, and the photosensitive portion 104 is assembled on the semiconductor substrate 102. The photosensitive portion 104, which may be a CCD array, includes a plurality of photosensitive elements 106. Each such photosensitive element 106 may correspond, for example, in part to an image pixel generated by the photosensitive portion 104. The active area of the photosensitive portion 104 may be referred to as an “active region” that can convert light energy into electrical energy or electrical signals. Unless otherwise noted, the term “light” refers to electromagnetic energy in any part of the spectrum. Thus, for example, light or light energy includes the visible portion of the electromagnetic spectrum, the infrared (IR) portion, the near infrared (NIR) portion, and the ultraviolet (UV) portion.

  An inactive region 108 at least partially surrounds the photosensitive portion 104. The inactive area 108 without photosensitive elements may include various circuit elements, conductive traces, etc. for operating the photosensitive portion 104. For example, if the photosensitive portion 104 is a CCD array, the inactive area 108 may include circuitry that controls a matrix of CCD elements. Each of the photosensitive part 104 and the inactive area 108 may occupy any part of the area of the image sensor chip 100. The photosensitive portion 104 may be positive or rectangular with any aspect ratio (eg, width to height).

  The semiconductor substrate 102 may include any number of elements, including combinations of such elements, any of which may include additional impurities (eg, dopants). For example, the semiconductor substrate 102 may be silicon or germanium. In some embodiments, the thickness of the image sensor chip 100 may range from about 5-10 microns up to 1 millimeter.

  The image sensor chip 100 may be incorporated in an optical system that provides light to the image sensor chip 100 in a special manner. For example, in some implementations, the lens system may be configured to have a focal plane that coincides with the location of the image sensor chip 100. In a specific implementation, the lens system may be configured to have a focal surface that coincides with the curved surface of the curved version of the image sensor chip 100. In other implementations, the lens system may be configured to have a focal length that matches the focal length of the image sensor chip 100. The optical elements of the optical system (eg, lenses and / or mirrors) may determine, at least in part, the focal length and the location of the focal plane. Specifically, the portion of the optical system that provides light to the photosensitive portion 104 is at least partially such as the size of the photosensitive portion 104, the resolution of the photosensitive portion 104, and the positioning of the photosensitive portion 104 relative to the remainder of the optical system. The design may be based on the specific details of the photosensitive portion 104. The performance of the optical system depends on the overall design of the optical system as well as the design of each optical element of the optical system, which shows the optical interaction between the optical elements. For example, the light output of one lens may be the light input of a subsequent lens. In general, the quality of the optical elements and their arrangement with respect to each other increases with increasing resolution (eg, the density of photosensitive elements 106 such as CCD elements corresponding to pixels). For example, such quality may be based at least in part on parameters of individual optical elements, including but not limited to structural and optical aberrations, light transmission or reflection, light uniformity, positioning, and the like.

  2-6 illustrate various portions of an exemplary process for bending or shaping an image sensor chip, such as image sensor chip 100, according to some embodiments. Such a process may be performed by any entity, either manually (eg, by a human), automatically (eg, by a machine), or a combination thereof. As used herein, such entities, which may be, for example, a manufacturer, an assembler, a fabricator, a builder, are referred to as “fabricators”. Call it.

  FIG. 2 is a side view of an image sensor chip 200 and a bending substrate 202 according to various embodiments. The image sensor chip 200 includes a photosensitive portion 204 that may be, for example, the same or similar to the photosensitive surface 104 illustrated in FIG. In some implementations, the bending substrate 202 is bonded or laminated to the first surface 206 of the image sensor chip 200. The processor may use adhesive 208 to perform such bonding or lamination. However, in some implementations, no adhesive may be used. In various implementations, portions of the first surface 206 may not be bonded or adhered to the bending substrate 202. For example, certain regions of the first surface 206 are bonded or bonded to the bending substrate 202, while other certain regions of the first surface 206 are i) bending substrate 202 and first surface. An air gap (not shown) may be included between the substrate 206 and ii) the adhesive 208 may be absent between the bent substrate 202 and the first surface 206. The processor can at least partially transfer (and thus shape) tension from the bent substrate 202 to the image sensor chip 200, for example, by including specific regions of the first surface 206 that have voids or lack adhesive. You may control it.

  The first surface 206 includes a photosensitive portion 204 that is a photosensitive portion of the image sensor chip 200. The first surface 206 may include an inactive region 210 that may be, for example, the same or similar to the inactive region 108 illustrated in FIG. An arrow 212 indicates the incident direction of light configured so that the image sensor chip 200 receives light.

  The edge 214 of the image sensor chip 200 may or may not be aligned with the edge 216 of the bent substrate 202. In some implementations, the bent substrate 202 may extend beyond the edge 214 of the image sensor chip 200, as illustrated in FIG. In other implementations, the image sensor chip 200 may extend beyond the edge 216 of the bent substrate 202.

  The bending substrate 202 may comprise any of a number of materials, such as, for example, plastic, polymer, other organic compounds, combinations thereof, or the like. In some embodiments, the thickness of the bending substrate 202 may be at least several times greater than the thickness of the image sensor chip 200. As a specific example, the image sensor chip 200 may be about 5-10 microns thick and the bending substrate 202 may be about 50-100 microns thick. The thickness of the image sensor chip 200 may be much larger than 10 microns and the bent substrate 202 may be at least several times larger than the image sensor chip 200. In some implementations, different portions of the bent substrate 202 may have different thicknesses. The choice of material for the bending substrate 202 may be based at least in part on the stiffness of the material compared to the stiffness of the image sensor chip 200. The stiffness of the image sensor chip 200 may be based at least in part on the substrate material of the image sensor chip 200, which may be silicon or germanium, and the thickness of the image sensor chip 200. The stiffness of the bent substrate 202 may depend at least in part on the material and thickness used for the bent substrate 202. In some implementations, the materials and thickness used for the bent substrate 202 may be different for different portions of the bent substrate 202. Accordingly, the stiffness of the bent substrate 202 may vary across different portions of the image sensor chip 200. For example, the portion of the bent substrate 202 that is above the central region of the image sensor chip 200 may be relatively rigid compared to the portion of the bent substrate 202 that is above the edge region of the image sensor chip 200.

  The selection of the material for the bent substrate 202 may be based at least in part on the thermal properties of the material. For example, the selected material may be applied to the image sensor chip 200 at a temperature substantially below the temperature at which damage to the image sensor chip 200 may occur. Excessive temperature may damage the photosensitive portion 204, the semiconductor substrate, and / or inactive areas of the image sensor chip 200. For example, in the case of a silicon-based image sensor chip, temperatures below 200 degrees Celsius are safe and may not damage the image sensor chip 200. Similarly, such temperature considerations may apply to the process of removing material used for the bending substrate 202 from the image sensor chip 200.

  In addition to temperature considerations, the choice of material for the bending substrate 202 may be based at least in part on the ability to apply material to the image sensor chip 200 and subsequently remove material from the image sensor chip 200. . For example, the material may be relatively easy to laminate or bond the material to the image sensor chip 202 and / or leave any remaining material and / or any physical characteristics of the photosensitive portion 204. Without change, the material may be selected to leave the image sensor chip 200.

  FIG. 3 is a side view of a curved image sensor chip 300 and a bending substrate 302 that is exposed to various applied forces and torques, according to some embodiments. In some embodiments, the curved image sensor chip 300 and the bending substrate 302 may be the same or similar to the image sensor chip 200 and the bending substrate 202 prior to the bending illustrated in FIG. For example, the processor may apply a force 304 and / or torque 306 to the bending substrate 202 to introduce tension that deforms the image sensor chip 100 resulting in a curved image sensor chip 300. Such forces and / or torques applied to the bending substrate and / or image sensor chip may cause reaction forces that a structure (not shown) may be located at contacts that support or hold the bending substrate and image sensor chip. May cause. For example, a force that pushes down an object on the table causes a reaction force of the table that pushes up the object. For clarity in the drawings, no reaction force is illustrated here.

  The curved image sensor chip 300 includes a curved photosensitive portion 308 disposed on the curved first surface 310. An adhesive 312 that may be the same as or similar to the adhesive 208 may bond the curved image sensor chip 300 and the bending substrate 302 together.

  The processor may apply any of a number of types of forces to the bending substrate 302 to bend the image sensor chip 300. For example, a pressurized fluid or gas 314 adjacent to the bending substrate 302 may apply a force 304 against the bending substrate 302. In some implementations, the pressurized fluid or gas 314 indicated by the arrows in FIG. 3 is contained adjacent to at least a portion of the surface 316 of the bending substrate 302 (eg, included within a flexible sac or mechanical actuator). ) It may contain fluid or gas. The pressurized fluid or gas 314 may apply different forces 304 at different locations on the surface 316. In some cases, mechanical contact by a solid object (not shown) having any of a number of shapes may replace the pressurized fluid or 314 and apply force 304.

  In other implementations, the processor applies one or more mechanical devices 318 (one of which is shown in FIG. 3) to a portion of the bent substrate 302 to apply torque to the bent substrate 302. (For example, rotational torque) may be applied. For example, a processor may apply a mechanical device 318 to a portion of the bent substrate 302 near the edge 320. In some cases, the mechanical device 318 may apply torque near the edge of the bent substrate 302, while the pressurized fluid or gas 314 creates a force near the central region of the bent substrate 302. Such a combination of linear force and torque (eg, provided by pressurized fluid or gas 314) may be applied in any proportion relationship to each other. For example, the force applied to the bending substrate 302 by the pressurized fluid or gas 314 may be twice that applied by the mechanical device 318. Whether or not only such ratio and / or linear force or torque is applied simultaneously, at least in part, is a physical detail (e.g., stiffness, thickness) of image sensor chip 300 (before bending). And the like, and may depend on the desired shape of the curved image sensor chip 300. In some implementations, a processor may apply mechanical device 318 to edge 322 of image sensor chip 300 in addition to or instead of applying mechanical device 318 to edge 320 of bent substrate 302. .

  Hereinafter, the combination of the curved image sensor chip 300 and the bent substrate 302 is referred to as an assembly 324. In some implementations, the assembly 324 may be placed in contact with a rigid object, such as a back substrate. In this way, the shape of the assembly 324 may remain unchanged after forces and / or torques are no longer applied to the bending substrate 302.

  FIG. 4 is a side view of an assembly 324 that includes a curved image sensor chip 300 and a bending substrate 302 disposed on a back substrate 400 according to various embodiments. Specifically, the processor may have a curved image on the opposite side of the curved first surface 310 illustrated in FIG. 3 such that at least a portion of the curved second surface 402 contacts the molded surface 404. The curved second surface 402 of the sensor chip 300 may be bonded to the molded surface 404 of the back substrate 400. Arrow 406 shows the process of moving the curved second surface 402 and the shaped surface 404 towards each other. In some implementations, a physical device, such as a clamping mechanism or holding mechanism (not shown), carries the curved image sensor chip 300 by holding the curved image sensor chip by the edge 408 of the bending substrate 302. It's okay.

  The back substrate 400 includes a bottom surface 410 opposite the molded surface 404. In the top view, the back substrate 400 may be square, rectangular, circular, or any other shape. Although the curved image sensor chip 300 and the back substrate 400 are illustrated in FIG. 4 as having the same size, the sizes may be different. For example, the back substrate 400 may be larger than the curved image sensor chip 300. The shaped surface 404 may have a shape that corresponds to the desired shape of the curved image sensor chip 300. The shaped surface 404 may be spherical, parabolic, aspherical, or a composite shape having one or more inflection points, just to name a few books.

  The back substrate 400 may comprise any of a number of materials that are sufficiently rigid to resist the tendency that the assembly 324 may have to straighten from a curved shape. Such materials may include, for example, metals, semiconductor materials, plastics, glass, ceramics, and the like. Hereinafter, the combination of the assembly 324 and the back substrate 400 is referred to as an assembly 412.

  The bottom surface and / or side surface of the back substrate 400 may include, for example, holes and / or protrusions 414 for mounting the assembly 412 in the optical system. Accordingly, assembly 412 may be a stand-alone optical device that can be incorporated into an optical system. An adhesive 416 may be placed over the molded surface 404 or over the curved second surface 402 to bond the molded surface 404 and the curved surface together.

  FIG. 5 is a side view of an assembly 412 that includes a curved image sensor chip 300, a bent substrate 302, and a back substrate 400, according to various embodiments. In some implementations, the shape of the curved second surface 402 and the shaped surface 404 may not be the same as each other. For example, when a force and / or torque (eg, as depicted in FIG. 3) is no longer applied to the bending substrate 302 to bend the image sensor chip 300 into a curved shape, the bending substrate and the curved image sensor chip 300. May have a tendency to become straight (eg, by elasticity). In some cases, forces and / or torques may be applied to the overshaped curved image sensor chip 300 to compensate for such trends. In other cases, such straightening may result in a curved second surface 402 having a different curvature or shape than the shaped surface 404. Such a difference may result in a gap or void 500 between the shaped surface 404 and any portion of the curved second surface 402. Such a gap or gap does not necessarily adversely affect the optical performance of the curved image sensor chip 300. This is because the gap or gap is on the side of the image sensor chip 300 opposite the curved photosensitive portion 308 (FIG. 3). In some cases, adhesive 416 may fill gaps or voids 500 so that assembly 412 is rigid and faithful. However, such a gap or gap may indicate that the shape of the curved image sensor chip 300 is not precisely the desired shape. Accordingly, the processor may apply one or more forces to the assembly 412 and the back substrate 400 so that the shape of the curved image sensor chip 300 has the shape of the shaped surface 404. In other words, the processor may squeeze the assembly 324 and the back substrate 400 together so that the curved image sensor chip 300 may deform into the shape of the molded surface 404. Concomitantly, any excess adhesive 416 may be extruded from between the assembly 324 and the back substrate 400.

  FIG. 6 is a side view of a curved image sensor chip 300 and back substrate 400 after removal of the bending substrate 302 in accordance with various embodiments. Such removal exposes the photosensitive portion 308 so that the photosensitive surface 308 can receive light that may be provided by an optical system that includes the image sensor chip 300. A combination of the image sensor chip 300 and the back substrate 400 is referred to as a molded optical sensor module 600. The molded optical sensor module 600 may be incorporated into the optical system as an optical element and may be mounted in the optical system using holes and / or protrusions 414. Specifically, a processor may build a molded photosensor module 600 and provide the molded photosensor module 600 to an assembler (which may be the same or different entity as the processor). The assembler may use the molded optical sensor module 600 as an image sensor that may be incorporated into the optical system.

  FIG. 7 is a side view of a configuration 700 that includes an image sensor chip 702 and a bent substrate 704 that is placed over the image sensor chip by deposition, according to various embodiments. The image sensor chip 702 includes, for example, a photosensitive portion 706 that may be the same as or similar to the photosensitive portion 104 illustrated in FIG. A bent substrate 704 is deposited on the first surface 708 of the image sensor chip 702. The processor may place the bent substrate over the image sensor chip 702 using any of a number of deposition techniques. Some examples of deposition techniques are spin coating, vapor deposition, sputtering and the like. In various implementations, the portion of the first surface 708 may not necessarily contact the bent substrate 704. For example, the bending substrate 704 may be deposited directly on a specific area of the first surface 708, while other specific portions of the first surface 708 are the bending substrate 704 and the first surface. A non-contact area (not shown) between 708 may be included. Such non-contact areas may be areas that lack the adhesive or bonding features that exist between the first surface 708 and the bending substrate 704. Thus, such non-contact areas cannot transmit shear force or stress from the bending substrate 704 to the first surface 708.

  The first surface 708 includes a photosensitive portion 706 that is a photosensitive portion of the image sensor chip 702. The first surface 708 may also include an inactive region 710 that may be, for example, the same or similar to the inactive region 108 illustrated in FIG. An arrow 712 indicates the direction of incident light configured so that the image sensor chip 702 receives light.

  The edge 714 of the image sensor chip 702 may or may not be aligned with the edge of the bent substrate 704. In some implementations, the image sensor chip 702 may extend beyond the edge 716 of the bent substrate 704.

  The bending substrate 704 may comprise any of a number of such materials, such as, for example, plastic, polymer, other organic compounds, or combinations thereof. The processor can determine the material's ease of deposition, adhesive strength sufficient for transfer of stress and shear forces across the interface between the bent substrate 704 and the image sensor chip 702, chemical and thermal stability, etc. The material for the bending substrate 704 may be selected considering a number of attributes.

  Specifically, the material selection for the bent substrate 704 may be based at least in part on the thermal properties of the material. For example, the selected material may be applied to the image sensor chip 702 at a temperature substantially lower than the temperature at which damage to the image sensor chip 702 may occur. Excessive temperature may damage the photosensitive portion 706 of the image sensor chip 702, the semiconductor substrate, and / or inactive areas. For example, for silicon, temperatures below about 200 degrees Celsius may be safe and not damage the image sensor chip 702. Similarly, such temperature considerations apply to the process of removing material used for the bending substrate 704 from the image sensor chip 702.

  In addition to temperature considerations, material selection for the bending material 704 is based at least in part on the ability to apply material to the image sensor chip 702 and then remove material from the image sensor chip 702. Good. For example, the material is relatively easy to deposit on the image sensor chip 702, and the material does not leave any residual material or has any physical characteristics of the photosensitive portion 708. It may be selected to leave the image sensor chip 702, vaporize, or disassemble without modification. For example, the processor may separate the bent substrate 704 from the image sensor chip 702 using a thermal de-bonding process. In some implementations, such a process may be performed in a nitrogen purged annular furnace.

  In some embodiments, the thickness of the bending substrate 704 may be at least several times greater than the thickness of the image sensor chip 702. As a specific example, the image sensor chip 702 may be about 5-10 microns thick and the bent substrate 704 may be about 50-100 microns thick. The thickness of the image sensor chip 702 may be much greater than 10 microns and may be at least several times thicker than the image sensor chip 702, which may be a bent substrate 704, a thickness of up to 1 millimeter or more. In some implementations, different portions of the bent substrate 704 may have different thicknesses. The selection of material for the bending substrate 704 may be based at least in part on the stiffness of the material compared to the stiffness of the image sensor chip 702. The stiffness of the image sensor chip 702 may depend at least in part on the substrate material and thickness of the image sensitive chip 702, which may be silicon or germanium. The stiffness of the bending substrate 704 may depend, at least in part, on the material and thickness used for the bending substrate 704. In some implementations, the material and thickness used for the bending substrate 704 may be different for different portions of the bending substrate 704. Accordingly, the stiffness of the bent substrate 704 may vary across different portions of the image sensor chip 702. For example, the portion of the bent substrate 704 that spans the central region of the image sensor chip 702 may be relatively rigid compared to the portion of the bent substrate 704 that spans the edge region of the image sensor chip 702.

  FIG. 8 is a side view of a configuration 800 that includes a curved image sensor chip 802 and a bending substrate 804 exposed to various applied forces and torques, according to some embodiments. In some embodiments, the curved image sensor chip 802 and the bent substrate 804 may be the same or similar to the image sensor chip 702 and the bent substrate 704, respectively, prior to bending as illustrated in FIG. For example, the processor may apply force 806 and / or torque 808 to the bent substrate 804 to provide a curved image sensor chip 802. The curved image sensor chip 802 includes a curved photosensitive portion 810 disposed on the curved first surface 812.

  A processor may apply a number of types of forces to the bent substrate 804 to bend the image sensor chip 802. For example, a pressurized fluid or gas adjacent to the bending substrate 804 applies a force 806 against the bending substrate 804. In some implementations, the pressurized fluid or gas 814 indicated by the arrows in FIG. 8 may include a contained pressurized fluid or gas that presses at least a portion of the surface 816 of the bent substrate 804. Different portions of the contained pressurized fluid or gas 814 may apply forces 806 against the different surfaces 816 depending on where they span the surface 816. In some cases, mechanical contact by a solid object (not shown) having any of a number of shapes may apply force 806 instead of pressurized fluid or gas 814.

  In other implementations, the processor applies one or more mechanical devices 818 (one of which is schematically shown in FIG. 8) to a portion of the bent substrate 804, Torque (eg, rotational force) may be applied to the bent substrate 804. For example, a processor may apply a mechanical device 818 to a portion of the bent substrate 804 near the edge. In some cases, the mechanical device 818 may apply torque near the edge of the bent substrate 804, while the pressurized fluid or gas 814 generates a force near the central region of the bent substrate 804. Such combinations of linear forces (eg, generated by pressurized fluid or gas 814) or torques may be applied in any ratio relationship to each other. For example, the force applied to the bending substrate 804 by the pressurized fluid or gas 814 may be twice that applied by the mechanical device 818. Such ratios, and whether or not only linear force and / or torque are applied simultaneously, at least in part, are the physical properties of image sensor chip 802 (before image sensor chip 802 is curved). The details (eg, stiffness, thickness, etc.) and the desired shape of the curved image sensor chip 802 may depend. In some implementations, a processor may apply mechanical device 818 to edge 822 of image sensor chip 802 in addition to or instead of applying mechanical device 818 to edge 820 of bent substrate 804. . The curved second surface 824 of the curved image sensor chip 802, opposite the curved first surface 812, may be placed in contact with a rigid object, such as a back substrate. In this way, the shape of the configuration 800 may remain unchanged after forces and / or torques are no longer applied to the bending substrate 804.

  FIG. 9 is a side view of an assembly 900 that includes a curved image sensor chip 802 and a back substrate 902 according to various embodiments. Specifically, the processor forms the curved second surface 824 of the curved image sensor chip 802 into the back substrate 902 such that at least a portion of the curved second surface 824 is in contact with the molded surface 904. May be joined to the raised surface 904. In some implementations, a curved image sensor chip 802 carries a curved image sensor chip 802 by holding the curved image sensor chip by the edge 820 of the bent substrate 804, such as a clamping mechanism or a holding mechanism (not shown). Good.

  In some implementations, the processor may remove the bent substrate 804 from the curved image sensor chip 802 after bonding the curved image sensor chip 802 to the back substrate 902. The bent substrate 804 may be removed by any of a number of techniques that do not damage the photosensitive portion 810. For example, the bent substrate 804 may include a material that evaporates, evaporates, or decomposes after sufficient heating. In other embodiments, the bending substrate 804 may comprise a material that can be chemically etched or dissolved.

  Removal of the bent substrate 804 exposes the photosensitive portion 810 so that the photosensitive portion 810 can receive light that may be provided by an optical system that includes a curved image sensor chip 802. The assembly 900 may be incorporated into the optical system as an optical element, and the assembly 900 may be mounted in the optical system using holes and / or protrusions 906 that may be disposed on the side or bottom surface 908 of the back substrate 902. . The bottom surface 908 is on the opposite side of the molded surface 904. Specifically, the processor may build the assembly 900 and provide the assembly 900 to the assembler (which may be the same entity as the processor). An assembler may use the assembly 900 as an image sensor, and the image sensor may be incorporated into the optical system.

  In the top view, the back substrate 902 may be square, rectangular, circular, or any other shape. Although the curved image sensor chip 802 and the back substrate 902 are illustrated in FIG. 9 as having the same size, the sizes may be different. For example, the back substrate 902 may be larger than the curved image sensor chip 802. The shaped surface 904 may have a shape that corresponds to the desired shape of the curved image sensor chip 802. The shaped surface 904 may be spherical, parabolic, aspherical, or a composite shape having one or more inflection points, to name just a few.

  The material and other characteristics of the back substrate 902 may be the same or similar to the back substrate 400 described above. An adhesive 910 may be placed over the molded surface 904 or over the curved second surface 824 to bond the molded surface 904 and the curved second surface 824 together.

  In some implementations, the shape of the curved second surface 824 and the shaped surface 904 may not be the same as each other. For example, when force and / or torque is no longer applied to the bending substrate 804 to shape the image sensor chip 802 into a curved shape, the bending substrate and the curved image sensor chip 802 are linear (eg, by elasticity). May have a tendency to In some cases, forces and / or torques may be applied to the overshaped curved image sensor chip 802 to compensate for such trends. In other cases, such straightening may result in a curved second surface 824 having a different curvature or shape than the shaped surface 904. Accordingly, the processor may apply one or more forces to the configuration 800 and the back substrate 902 so that the shape of the curved image sensor chip 802 has the shape of the molded surface 804. . In other words, the processor may squeeze the configuration 800 and the back substrate 902 together such that the curved image sensor chip 802 is bent into the shape of the molded surface 904.

  FIG. 10 is a cross-sectional view of an optical system 1000 that includes an image sensor module 1002 and a lens assembly 1004 in accordance with various embodiments. Specifically, the image sensor module 1002 includes a curved image sensor chip 1006, a bent substrate 1008, and a back substrate 1010. The curved image sensor chip 1006 includes a photosensitive portion 1012. The bent substrate 1008 may be a transparent material that allows light from the lens assembly 1004 to reach the photosensitive portion 1012. The curved image sensor chip 1006, the bent substrate 1008, and the back substrate 1010 are respectively curved curved image sensor chips 300 or 802, bent substrates 302 and 804, and back substrates 400 and 902 illustrated in FIGS. It may be the same or similar. In some implementations, the image sensor module 1002 may not include the back substrate 1010. In this case, the bending substrate may be sufficiently rigid to maintain the curved shape of the curved image sensor chip 1006. The bending substrate 1008 may comprise a material that can be made to be rigid after the process of bending the curved image sensor chip 1006. For example, such materials may be rigid at relatively low temperatures, while they may be flexible or malleable at higher temperatures. Thus, the bending process of forming the curved image sensor chip 1006 occurs at a high temperature, and then the cooling process “freezes” the shape of the curved image sensor chip 1006.

  The curved image sensor chip 1006 (or more precisely, the photosensitive portion 1012) may have a shape that produces a focal length. Such focal length may be considered when placing the image sensor module 1002 in the optical system 1000. Specifically, the lens assembly 1004 receives the light 1014, optically affects the light, and generates a light output 1016 that focuses the image onto the curved image sensor chip 1006. The curved image sensor chip 1006 may be designed and may be at a distance 1018 from the lens assembly 1004. The distance 1018 may be at least approximately equal to the focal length of the curved image sensor chip 1006. In some embodiments, the inverse of the focal length of the curved image sensor chip 1006 may be at least approximately equal to the radius of curvature of the curved image sensitive chip 1006. Lens assembly 1004 and image sensor module 1002 may be aligned along optical axis 1020.

  FIG. 11 is a cross-sectional view of an optical system 1100 that includes an image sensor module 1102 and a lens assembly 1104 according to various embodiments. The lens assembly 1104 may be similar or identical to the lens assembly 1104 illustrated in FIG. 10, for example. The image sensor module 1102 includes a curved image sensor chip 1106 and a back substrate 1108. The image sensor module 1102 does not include a bent substrate, but a processor may use the bent substrate to provide a curved image sensor chip 1106 shape. Such a bent substrate may be removed after attaching the curved image sensor chip 1106 to the back substrate 1108.

  The curved image sensor chip 1106 includes a photosensitive portion 1110 that is exposed to light generated by the lens assembly 1104 (eg, which may be an image on the surface of the photosensitive portion 1100). The curved image sensor chip 1106 and back substrate 1108 may be similar or identical to the curved image sensor chip 300 or 802 and back substrate 400 and 902, respectively, illustrated in FIGS.

  The curved image sensor chip 1106 (or more precisely, the photosensitive portion 1110) may have a shape suitable for a lens having a specific focal length. Such focal length may be considered when placing the image sensor module 1102 in the optical system 1100. Specifically, the lens assembly 1104 receives light 1112, optically affects the light, and outputs light that focuses the image onto a curved image sensor chip 1106 at a distance 1116 from the lens assembly 1104. It may be designed to produce 1114. The distance 1116 may be at least approximately equal to the focal length of the curved image sensor chip 1106. In some implementations, the inverse of the focal length of the curved image sensor chip 1106 may be at least approximately equal to the radius of curvature of the curved image sensor chip 1106. The lens assembly 1104 and the image sensor module 1102 may be aligned along the optical axis 1118.

  FIG. 12 is a side view of a configuration 1200 that includes an image sensor chip 1202 and a bending substrate 1204 that includes various notches and grooves 1206, according to some embodiments. Although the edges of the bent substrate 1204 are illustrated as extending beyond the edges of the image sensor chip 1202, such edges may or may not be aligned with each other. In some implementations, the edge of the image sensor chip 1202 extends to the edge of the bent substrate 1204 or extends beyond the edge of the bent substrate 1204, which is true when the bent substrate 1204 is placed over the image sensor chip 1202. It may be full.

  Notches and / or grooves 1206 may be present in the bending substrate 1204 to at least partially control the amount and distribution of bending stress in the bending substrate 1204 in response to applied force and / or torque 1208. By introducing such control of bending stress, the shape of the deformation of the bending substrate 1204 in response to the applied force and / or torque 1208 may be adjusted to add a desired shape to the image sensor chip 1202. The notches and / or grooves 1206 affect the thickness of the portion of the bent substrate 1204. For example, the bending substrate 1204 may have T1, in which case notches and / or grooves 1206 are not disposed. However, the bending substrate 1204 may be thinned to a thickness T2 by notches and / or grooves 1206. Such different thicknesses of the bending substrate 1204 can affect the degree of bending of the bending substrate 1204.

  In addition to different thicknesses due to the presence of notches and / or grooves 1206, different portions of the bent substrate 1204 may have different thicknesses in different regions. In other words, Ti may be different for different parts of the bent substrate 1204. Also, the material used for the bending substrate 1204 may be different for different portions of the bending substrate 1204. Accordingly, the stiffness of the bent substrate 1204 is based at least in part on the presence and location of notches and / or grooves 1206, the material of the bent substrate 1204, and / or the thickness of various portions of the bent substrate 1204. It may be different over 1202 different parts.

  Any number of notches and / or grooves 1206 may be disposed on any portion of the bending substrate 1204. The notches and / or grooves 1206 may be disposed adjacent to the photosensitive portion 1210 of the image sensor chip 1202. Notches and / or grooves 1206 may be disposed in the bending substrate 1204. The notches and / or grooves 1206 may have any shape, size, or depth. In some implementations, the notches and / or grooves 1206 may be filled with a material that is different from the material of the bending substrate 1204.

  FIG. 13 is a top view of a bending substrate 1300 that includes a series of notches and / or grooves 1302 that are concentrically distributed around a central region of the bending substrate 1300 in accordance with a number of embodiments. The distance between concentric notches and / or grooves 1302 is an image sensor chip (not shown in FIG. 13) that is attached (eg, bonded or glued) to the bending substrate 1300. It may be different to affect the specific shape of the bend. The notches and / or grooves 1302 may be disposed on the surface of the bending substrate 1300 on the same side as or opposite to the image sensor chip.

  FIG. 14 is a side view of a configuration 1400 that includes a curved image sensor chip 1402 and a bending substrate 1404 that includes various notches and grooves 1406 according to some embodiments. For example, the configuration 1400 may be the same as or similar to the configuration 1200 that is exposed to the force and / or torque 1208 as depicted in FIG. Curved image sensor chip 1402 includes a similarly curved photosensitive portion. Such curvature of the image sensor chip 1402 and the photosensitive portion 1408 may depend, at least in part, on the characteristics of the notches and / or grooves 1406, such as their placement, shape, size, and the like.

  FIG. 15 is a side view illustrating a neutral axis 1500 of configuration 1502 that includes an image sensor chip 1504 and a bending substrate 1506 in accordance with various embodiments. The neutral shaft 1500 results from the applied force and / or torque 1508. Neutral axis 1500 is a virtual surface that separates the material under tension from the material under compression. For example, in response to force and / or torque 1508, the bending substrate 1506 is under compression above the neutral axis 1500 and under tension below the neutral axis 1500. The image sensor chip 1504 is located below the neutral axis 1500, so it is under tension. The location of the neutral axis 1500 relative to the location of the image sensor chip 1504 may affect the amount of bending of the image sensor chip 1504. The location and “shape” of the neutral axis 1500 may be at least partially the placement, shape and size of notches and / or grooves that may be present in the bending substrate 1506, and the image sensor chip 1504 and bending substrate 1506. It can depend on a number of factors, such as stiffness and thickness. Thus, the processor may control where to place the neutral shaft 1500 based on these factors.

  FIG. 16 is a cross-sectional view illustrating the curvature of a curved image sensor chip 1600 attached to a back substrate 1602 according to various embodiments. The curved image sensor chip combination coupled to the back substrate may include a stand-alone optical device that may subsequently be incorporated into the optical system. The optical axis 1604 of such an optical system is shown in relation to the image sensor chip 1600. The focal length of the image sensor chip 1600, based at least in part on the curved shape of the image sensor chip 1600, may be a significant factor when the image sensor chip 1600 is incorporated into an optical system. When the shape of the image sensor chip 1600 is substantially spherical, the focal length of the image sensor chip 1600 may be at least approximately equal to the inverse of the radius of curvature R of the image sensor chip 1600. If the image sensor chip 1600 has an aspherical shape, the radius of curvature of the image sensor chip 1600 changes according to the distance from the optical axis 1604. The optical system including the image sensor chip 1600 may be designed to accommodate such a variable radius of curvature.

  17 and 18 are cross-sectional views illustrating the shape of the photosensitive portion of a curved image sensor chip, according to some embodiments. In FIG. 17, the photosensitive portion 1700 of the curved image sensor chip 1702 has a spherical or aspherical shape. Such a shape does not have an inflection point. The photosensitive portion 1700 is concave. On the other hand, as illustrated in FIG. 18, the photosensitive portion 1800 of the curved image sensor chip 1802 has a complex shape including one or more inflection points. The portion of the photosensitive portion 1800 may include a spherical or aspherical shape. Such complex shapes can be useful in many optical systems. A bent substrate as described above may be designed to provide a complex shape of the photosensitive portion 1800 in combination with the applied force and / or torque.

  FIG. 19 is a top view of a configuration 1900 that includes an image sensor chip 1902 and a bending substrate 1904 in accordance with various embodiments. The bent substrate 1904 is on the side of the image sensor chip 1902 including the photosensitive portion 1906. Although the edges of the bent substrate 1904 are illustrated in FIG. 19 as extending beyond the edges of the image sensor chip 1902, such edges may be aligned with each other. Round one or more corners 1908 of the image sensor chip 1902 to avoid relatively sharp corners that tend to collect stresses that may result from forces and / or torques applied to the bending substrate 1904. Good. Such stress concentrations can lead to undesirable cracking or buckling of the image sensor chip 1902. For example, a crack that begins in or near the corner 1908 may propagate across the image sensor chip 1902 in any direction, rendering the image sensor chip 1902 useless. In some implementations, the bending substrate 1904 may include rounded corners 1910.

  FIG. 20 is a flow diagram illustrating an example process 2000 for bending an image sensor chip, according to some embodiments. For example, such an image sensor chip may be the same as or similar to the image sensor chip 300 or the image sensor chip 802 shown in FIGS. 3 and 8, respectively. Process 2000 may be similar or identical to the process depicted in FIGS. 2-6 and 7-9 and may be performed by a processor. At block 2002, the processor may place a bending substrate over the first surface of the imaging sensor chip. The first surface of the imaging sensor chip includes an optical sensor that generates an electrical signal in response to received light. At block 2004, the processor may bend the bending substrate to apply a force on the image sensor chip to produce a curved imaging sensor chip. At block 2006, the processor may attach the curved second surface of the imaging sensor chip to the back substrate. The second surface is opposite the first surface of the curved imaging sensor chip. At block 2008, the processor may remove the bent substrate from the first surface of the imaging sensor chip.

(Example section)
A: disposing a bending substrate over the first surface of the imaging sensor chip and bending the bending substrate to apply a force to the imaging sensor chip (image sensor chip) to provide a curved imaging sensor chip; The method wherein the first surface of the imaging sensor chip includes an optical sensor that generates an electrical signal in response to the received light.

  B. Attaching the curved second surface of the imaging sensor chip to the back substrate and removing the bent substrate from the first surface of the imaging sensor chip, wherein the second surface is opposite the first surface. The method according to paragraph A,

  C. The method of paragraph B, wherein removing the bent substrate from the first surface of the imaging sensor chip includes thermally separating the bent substrate from the first surface of the imaging sensor chip.

  D. The method of paragraph B, wherein the back substrate includes at least one curved surface having a radius of curvature that is at least approximately equal to the reverse focal length of the first surface of the imaging sensor chip.

  E. The method of paragraph A, wherein disposing the bending substrate over the first surface of the imaging sensor chip includes attaching the bending substrate to the first surface of the imaging sensor chip using an adhesive.

  F. The method of paragraph A, wherein disposing the bent substrate over the first surface of the imaging sensor chip includes forming the bent substrate over the first surface of the imaging sensor chip using a deposition process. .

  G. The method of any one of paragraphs A through F, further comprising forming a notch or groove in the bent substrate prior to placing the bent substrate over the first surface of the imaging sensor chip.

  H. The method of any one of paragraphs A through G, wherein bending the bent substrate includes applying a pressurized gas or liquid over the bent substrate.

  I. The method according to any one of paragraphs A through H, wherein the first surface of the curved imaging sensor chip is concave.

  J. et al. A curved imaging sensor chip (image sensor chip) having a first side surface and an opposite second side surface, wherein the first side surface includes an optical sensor that generates an electrical signal in response to received light. And a bent substrate covering the first side surface of the curved imaging sensor chip.

  K. The apparatus of paragraph J, further comprising a back substrate covering the second side of the curved imaging sensor chip.

  L. The apparatus of paragraphs J through K, wherein the bent substrate includes a deposited material that is bonded to the first side of the imaging sensor chip curved by deposition.

  M.M. The apparatus of paragraphs J through K, wherein the bending substrate is bonded to the first side of the imaging sensor chip curved by an adhesive.

  N. The apparatus of paragraphs J through M, wherein the bent substrate includes one or more notches or grooves.

  O. The apparatus of paragraphs J through N, wherein the curved imaging sensor chip includes rounded corners.

  P. The apparatus of paragraphs J through O, wherein the curved imaging sensor chip has a radius of curvature that is at least approximately equal to the back focal length of the first side of the curved imaging sensor chip.

  Q. A curved imaging sensor chip having a first side and an opposite second side, wherein the first side includes a photosensor that generates an electrical signal in response to the received light; and a curved A system comprising: a substrate covering a first side of the imaging sensor chip; and a back substrate covering a second side of the curved imaging sensor chip.

  R. The system of paragraph Q, further comprising one or more lenses that direct electromagnetic energy to the first surface of the curved imaging sensor chip.

  S. The system of paragraphs Q through R, wherein the curved imaging sensor chip includes germanium and the directional electromagnetic energy includes infrared energy.

  T. T. The system of paragraphs Q through S, wherein the stiffness of the curved imaging sensor chip is substantially greater than the stiffness of the bent substrate.

(Conclusion)

  Although the subject matter has been described in language specific to structural arrangements and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific configurations or acts described. Rather, the specific configurations and steps are disclosed as exemplary forms of implementing the claims.

  All of the methods and processes described above may be implemented fully automated via software code modules executed by one or more general purpose computers or processors. A code module may be stored in any type of computer readable media, computer storage media, or other computer storage devices. Some or all of the methods may alternatively be embodied in specialized computer hardware, such as, for example, a quantum computer or a quantum annealing device.

  In particular, conditional such as “can”, “could”, “may” or “may” Unless otherwise noted, certain languages are understood within the context that a particular embodiment includes a particular configuration, element, and / or step, but that other embodiments do not. Thus, such conditional language is such that a particular configuration, element, and / or step is required anyway for one or more embodiments, or one Or more than one embodiment, with or without user input or user prompt, with particular configurations, elements, and / or steps included in any particular embodiment, or any It is generally not intended to imply that it necessarily includes logic to determine what should be done in this particular embodiment.

  A connection language such as “at least one of X, Y, or Z” is an item, term, etc. that is either X, Y, Z, or a combination thereof, unless otherwise specified. It should be understood as a communication.

  Any conventional descriptions, elements, or blocks in the flow diagrams set forth herein or depicted in the accompanying drawings may be used to implement one or more specific logic functions or elements in the practice. Must also be understood as potentially representing a portion, segment, or module of code that contains many executable instructions. Alternative implementations are included within the scope of the embodiments described herein, and their elements or functions are substantially simultaneous, depending on the functionality included as understood by those skilled in the art. Or it may be deleted from what is shown or discussed, including the reverse order, or performed in a disjoint order.

  It should be emphasized that many variations and modifications may be made to the above-described embodiments, and that those elements should be understood as being within other acceptable embodiments. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

Claims (15)

Placing a bending substrate over a first surface of the imaging sensor chip; and bending the bending substrate to apply a force to the imaging sensor chip to provide a curved imaging sensor chip;
The first surface of the imaging sensor chip includes an optical sensor that generates an electrical signal in response to received light.
Method. Attaching a second surface of the curved imaging sensor chip to a back substrate; and removing the bent substrate from the first surface of the imaging sensor chip;
The second surface is opposite the first surface;
The method of claim 1.   The method of claim 2, wherein removing the bent substrate from the first surface of the imaging sensor chip comprises thermally separating the bent substrate from the first surface of the imaging sensor chip.   The method of claim 2, wherein the back substrate includes at least one curved surface having a radius of curvature that is at least approximately equal to a reverse focal length of the first surface of the imaging sensor chip.   The disposing the bent substrate on the first surface of the imaging sensor chip includes attaching the bent substrate to the first surface of the imaging sensor chip using an adhesive. The method according to 1.   Placing the bent substrate on the first surface of the imaging sensor chip includes forming the bent substrate on the first surface of the imaging sensor chip using a deposition process. The method of claim 1.   The method of claim 1, further comprising forming a notch or a groove in the bent substrate prior to placing the bent substrate on the first surface of the imaging sensor chip.   The method of claim 1, wherein bending the bent substrate comprises applying a pressurized gas or liquid to the bent substrate.   The method of claim 1, wherein the first surface of the curved imaging sensor chip is concave. A curved imaging sensor chip including a first side and an opposite second side, wherein the first side includes an optical sensor that generates an electrical signal in response to received light;
A bent substrate covering the first side surface of the curved imaging sensor chip,
apparatus.   The apparatus according to claim 10, further comprising a back substrate covering the second side surface of the curved imaging sensor chip.   The apparatus of claim 10, wherein the bent substrate is bonded to the first side of the curved imaging sensor chip by an adhesive.   The apparatus of claim 10, wherein the curved imaging sensor chip has a radius of curvature that is at least approximately equal to a reverse focal length of the first side of the curved imaging sensor chip. A curved imaging sensor chip including a first side and an opposite second side, wherein the first side includes an optical sensor that generates an electrical signal in response to received light;
A substrate covering the first side surface of the curved imaging sensor chip;
A back substrate covering the second side surface of the curved imaging sensor chip,
system.   The system of claim 14, wherein the stiffness of the curved imaging sensor chip is substantially greater than the stiffness of the bent substrate.

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